(a) Representative Field Potential response in layer V of the RFA in sham (Black), stroke untreated (Red) and Robot+BoNT (Blue) animals after single pulse stimulation in the contralateral RFA. (b) Current source density analysis of the cortical field potential response to optogenetic stimulation, in stroke untreated (top) and Robot+BoNT (bottom) groups. Warm colors (yellow and red) represent current sinks and cool colors (dark and light Blue) represent current sources. (c, d) Mean amplitude of the early negative (c) and late positive (d) components of evoked field potentials in sham (Black), stroke untreated (Red) and Robot+BoNT (Blue) group. Results from adjacent channels (depths) were pooled to show responses in superficial (Sup), Sup/Middle, Middle/deep and Deep layers. The early FP component in the ipsilesional RFA of rehabilitated animals is comparable to sham only in layer V (p=0.089), while the late positive wave is comparable to controls in superficial/middle to deep layers (sup p=0.436, sup./middle p=0.07, middle/deep p=0.179, deep p=0.676) and significantly lower with respect to stroke untreated in middle layers (sup./middle p=0.009, middle/deep p=0.002, Two-way Anova, followed by Tukey test between groups). (e) Paired Pulse ratio in Robot+BoNT(Blue) was comparable to sham across all the cortical layers (sup p=0.659, sup./middle p=0.267, middle/deep p=0.164, deep p=0.197, Two-way Anova, followed by Tukey test between groups) and significantly different from stroke untreated except from superficial layers (sup./middle p=0.006, middle/deep p=0.001, deep p=0.005, Two-way Anova, followed by Tukey test, Robot+BoNT vs Stroke untreated). *p<0.05; **p<0.01; ***p<0.001, data are mean ±SE. (f) MUA triggered by 50 ms ISI paired-pulse stimulation across all cortical layers in the target hemisphere in sham (top), stroke untreated (middle) and Robot+BoNT (bottom) mice. MUA values are normalized to the first peak response value, for each channel separately. Roman numerals indicate cortical layers.